Only part 2 to be done. I already have done Part 1 myself. PArt 1 was on NI Multisim Live and part 2 is on real hardware which is ANAlog Discover kit
Microsoft Word - EEET2255 Assignment 1 - 2020.docx 1 EEET2255 Electronics Assignment 1 Released: 1-April-2020 General Instructions • The Assignment 1 due date is by 11:59pm, Friday 24-April-2020. • This assignment is project based, including calculations, simulations and measurements. • The simulations are to be done using NI Multisim Live (https://www.multisim.com) and the measurements are to be done using the NI Analogue Discovery II. • Assignment 1 contributes up to 20% of your final mark for the course. • The full marks for assignment 1 are 40. Marks for each question are shown. • Please submit an electronic copy (in PDF format) through Canvas. • In your submission, where applicable, include your schematics, a description of your simulation settings, simulation results and measurement results (e.g. signal waveforms, gain plots…). • Late submissions without an approved Special Consideration will result in the following penalties: o Late by 1 day or less – 30% penalty o Late by 2 days – 60% penalty o Late by 3 days – 90% penalty o Late by 4 days or more – will be marked 0 2 Project – Frequency Response of the Non-inverting Op-Amp Circuit Project Aim • Investigate the frequency response of the non-inverting op-amp circuit Parts List • NI Multisim Live (available online) • NI Analog Discovery II (driving software: Digilent WaveForms) • Components: o One 741 op-amp o Breadboard and wires o Resistors: 100Ω, 1kΩ, 2 x 10kΩ. Project Description and Tasks Part 1: Calculations and Simulations The op-amp is very popular and has many uses, since it requires few external components and circuitry is easy to design. Figure 1 shows an open-loop op-amp circuit. Figure 1 Open-loop op-amp circuit Q1: Build the circuit shown in Figure 1 in Multisim Live and use the 3-terminal op-amp model (3T_VIRTUAL). Run an AC simulation sweeping from 1 Hz to 10 GHz (1e10 Hz). Display the output voltage versus frequency using a dB scale for the output voltage. What is the gain of the amplifier (in dB) at 1 Hz and the 3 dB bandwidth of the amplifier (i.e. the frequency where the gain has dropped by 3 dB from its value at 1 Hz)? [4 marks] Q2: Setup a transient simulation to analyse the amplifier circuit from 0 seconds to 5 seconds. Then open the op-amp settings by double clicking on the op-amp symbol and change the Vomp and Vomn values from the default values to 100 V and -100 V, respectively. This changes the power supply provided to the op-amp. Re-run the transient simulation and explain the differences you see in the output voltage waveform for the two cases. [4 marks] 3 The open-loop op-amp configuration is not used in practice. Usually, there is a feedback connection between the output and the inverting input. A practical op-amp circuit with feedback is the non-inverting amplifier shown in Figure 2. Figure 2 Non-inverting op-amp circuit Q3: Calculate the overall gain of the circuit shown in Figure 2 under two conditions: (1) the op-amp has infinite open-loop gain (A = ∞); and (2) the op-amp has an open-loop gain of A = 200k. Compare your calculated results. [4 marks] Q4: Build the circuit shown in Figure 2 in Multisim Live (use the UA741CD op-amp model). Use an AC sweep analysis over the frequency range of 1 Hz to 10 GHz. Compare the simulated gain (at 1 Hz) with the gain calculations from Q3 when: (1) the op-amp has infinite open-loop gain (A = ∞); and (2) the op-amp has an open-loop gain of A = 200k. [4 marks] Q5: From the simulation results obtained in Q4, determine the 3 dB bandwidth of the amplifier. Compare the bandwidth result obtained with the open-loop bandwidth obtained in Q1. How does the feedback connection affect the circuit bandwidth and the circuit gain? [2 marks] Q6: For the circuit in Figure 2, run a transient simulation over a time interval of 0 to 5 seconds. Repeat the simulations for Vsource peak voltage values of 0.4 V and 0.1 V. In all three cases, include the gain ?! = "! "" in your output plots. Compare the results with the gain values calculated in Q3 and explain any differences. [4 marks] Q7: Comparing the results you obtained in Q1 with those you obtained in Q4, how does the feedback connection affect the circuit bandwidth? [2 marks] 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 A A B B C C D D E E F F G G VCC 5V VCC -5V R 100 R1 1 R2 10 V 1V 1H 0 RL 10 U1 UA741CD 3 2 4 1 VLV VV Rin Rout 4 Part 2: Experiments and Measurements Build the inverting op-amp we studied in Figure 2 using the breadboard. Set the “Supplies” of the Analog Discovery II to output ±5V DC voltages and connect the power supplies to the op-amp (i.e., dual power supply). Set the “Wavegen” to 1 kHz and the peak amplitude to 0.1 V to provide the input signal (use the sine wave). Q8: Measure and record the output voltage waveform. What is the measured gain of the circuit? How does this compare with your simulation result obtained in Q6? [2 marks] Q9: Change the input signal frequency to 100 Hz, 1 MHz and 10 MHz. Measure and record the output waveforms at each frequency. How does the change of signal frequency affect the output experimentally? [4 marks] Q10: Compare the measurement results in Q9 with the simulation results obtained in Q4 (results with A = ¥ and A = 200k). Discuss the similarities and differences. What are the possible causes of the differences? [4 marks] Change the input signal frequency back to 1 kHz. Gradually increase the frequency until you see the output waveform start to change (i.e. a decrease in gain and distortion of the waveform). Use the network analyser to view the frequency response of your amplifier circuit. Q11: How does the measured circuit 3 dB bandwidth compare with the open-loop op-amp bandwidth we simulated in Q1 and the closed-loop op-amp bandwidth we simulated in Q4? [4 marks] Part 3: Open Discussions Q12: Based on the lectures, tutorials, workshops and this assignment, discuss your opinion on why we use the op-amp together with the feedback connection. [2 marks] [Total: 40 marks] End of Assignment 1 EEET2255 Individual Assignment Marking Rubric The individual assignment in EEET2255 will be questions based, and the total mark allocated to each question (including each sub-section of equation) is given in the assignment. There are three major types of questions: (1) explanation and discussion; (2) theoretical calculation; and (3) circuit simulation and measurement. The marking rubric for each type is given below. Type 1: explanation and discussion: • 100% of total allocated mark: clear, comprehensive and accurate explanations and discussions are given; • 75% of total allocated mark: the explanations and discussions are clear and comprehensive in general, and mostly accurate; • 50% of total allocated mark: the explanations and discussions are clear but limited, and they are reasonably accurate; • 25% of total allocated mark: limited explanations and discussions are presented, and most of them are inaccurate; • 0% of total allocated mark: not presented. Type 2: theoretical calculation: • 100% of total allocated mark: correct result with clear analysis and calculation steps; • 75% of total allocated mark: clear analysis and calculation steps, mostly correct calculations, but incorrect final result; • 50% of total allocated mark: clear analysis and calculation steps, and 50% correct calculations; • 25% of total allocated mark: limited analysis and calculation steps, and mostly incorrect calculations; • 0% of total allocated mark: not presented. Type 3: circuit simulation and measurement: • 100% of total allocated mark: correct circuit schematic/photo with detailed description of simulation/measurement steps and correct results; • 75% of total allocated mark: correct circuit schematic/photo with limited description of simulation/measurement steps and mostly correct results; • 50% of total allocated mark: correct circuit schematic/photo with limited description of simulation/measurement steps and mostly incorrect results; • 25% of total allocated mark: incorrect circuit schematic/photo with limited description of simulation/measurement steps and incorrect results; • 0% of total allocated mark: not presented.